"vnd.sec.contact.phone" is the default local account that Samsung devices use to store contacts. It is usually recommended to use this account because the Contact app is perfectly suited to manage this account (for instance postal address may be split into street, zip code, town, etc.). That's why I usually recommend to use this account.
So if you create a contact in Device account (not BirdieSync account) on your Android device, the contact should be stored in "vnd.sec.contact.phone".
Synchronization of BirdieSync account address book:
If you prefer to use local BirdieSync account instead to store your contacts, then it's necessary to select it to be synchronized in BirdieSync configuration instead of "vnd.sec.contact.phone". Be aware that if you uninstall BirdieSync app, Android will remove BirdieSync account with all its contacts and events (BirdieSync app cannot have any control about it).
If you wish to change the address books which is selected to be synchronized ("BirdieSync" instead of "vnd.sec.contact.phone"), the easiest way is to use BirdieSync assistant
(menu "Assistant / Configure synchronization), selecting "Unique address book" mode.
Alternatively you may change the configuration manually:
These steps consider that address book mode is set to "Account" (which is the case if you have "vnd.sec.contact.phone" and "BirdieSync" address books listed).
- In BirdieSync Main window on the PC, select "Configuration" view
- In "Sources" column, select your Android source
- In "Content" column, select "Events"
- Set OFF the synchronization of "vnd.sec.contact.phone"
- Select "vnd.sec.contact.phone" address book and above the address book list click on the button with the circular arrow and the point, and select "Combine this address book with address books from other sources".
(this will reset synchronization between "vnd.sec.contact.phone" and Thunderbird address book)
- Select "BirdieSync" account address book and above the address book list on the right, click on the gear button and select "Set this address book as Main".
(this will allow to synchronize with the address book in Thunderbird also set as Main)
- Set ON "BirdieSync" address book
This way, "BirdieSync" address book on Android will be synchronized with Thunderbird address book selected to be synchronized, and set as Main.
You'll find more information in BirdieSync help (menu "Help/Help..." in section "Configuration/Folder").
Ensure that the preview of operations before synchronization is enabled: use menu File/Preview options (the option must be checked in blue), or the "Preview operations" icon on the right of the main synchronization progress bar (the button is COLORED if the preview is enabled)
Before any operation, I suggest you to backup your data as mentioned in this FAQ topic: